The term “manually-wound watches” designates the type of watches in which winding occurs by turning of the element, known as crown, that usually protrudes laterally outside the watch case. The crown is connected to the winding mechanism inside the watch, which comprises a spring which, if wound sufficiently, releases the energy necessary to move the hands and thus to operate the watch.
In order to wind such mechanism that comprises the spring, it is necessary to turn the crown about its axis.
The crown can be turned manually by the user; however, in some situations, a winding controlled by an electronic device or a faster winding than is attainable manually by a user may be necessary.
Several devices for winding manually-wound watches are known in the background art.
It is known to use electric or electronic devices provided with a power source, a motor and a system designed to transfer to the watch crown the rotation applied by the motor. The element suitable to jointly connect the crown to the axis that turns it is known as “spindle” and is actuated in known devices by means of a spring.
U.S. Pat. No. 6,439,761 discloses, for example, an electronic winding device with biaxial adjustment means for arranging the watch crown correctly with respect to the spindle of the device. Moreover, such device comprises an interface for adjusting periods, intervals and speeds of the rotation applied to the crown. An electronic sensor interrupts the winding when it detects that the watch has been fully wound.
However, such device is complicated and difficult to use because it forces the operator to perform a number of movements and attempts before he achieves the coaxial alignment of the crown with the spindle. Moreover, it is necessary to adjust the device according to the watch to be wound, thus causing very long preparation times. In particular, this characteristic makes it inconvenient to use the device for the sole purpose of occasionally is winding the watch.
Moreover, the presence of the means for obtaining correct positioning of the watch increases considerably the volume and weight of the device.
Another known device for winding manually-wound watches is disclosed in U.S. Pat. No. 5,988,871, which comprises a mechanism for opening and closing the spindle on the watch crown which is provided with a button connected to a spring and to an extensible arm. The spindle is composed of two claws and is connected to an end of the extensible arm. By pressing the button the arm is extracted and the spindle is opened. Once the watch has been positioned, the button is released and the arm retracts in the original position by means of the spring, while the spindle closes on the crown. This device has a mechanical friction system, which is adjusted manually for avoiding excessive loading of the spring of the mechanical watch and thus avoiding breakage of the mechanism inside it.
This device suffers problems related to the positioning of the crown axis with respect to the mechanism of the device. In particular, the alignment of the spindle axis with respect to the watch crown axis is initially entirely accidental. Only a correct alignment of the two axes leads to a precise and efficient winding of the watch, and this is determined exclusively by the user's skill.
Moreover, since manually-wound watches of different brands have different bulks as well as a different number of turns and winding torque, a regulator is provided to allow the user to adapt the device to the watch that he intends to wind. However, this is inaccurate and even risky, because the inner mechanism of the watch is very delicate and it is necessary to apply the right torque and an appropriate speed to the rotation of the crown in order to avoid damage to the mechanism and to the spring comprised in the watch.
Moreover, in known devices the use of the spring-loaded spindle as an element for mating between the device and the crown makes it necessary is to move the watch along the crown pivot axis. This leads to a need for subsequent adjustments of the watch support in order to avoid inner wear and friction of the watch proper or unwanted transitions of the crown from the winding position to the date-change or time-change position.
Moreover, in order to use a spring-loaded spindle it is necessary that the crown axis and the spindle axis be coaxial; otherwise significant cyclic torques are generated which could damage the watch.
Moreover, the use of a spring-loaded spindle might damage the crown and the watch case in case of a partial or excessive insertion of the spindle.
Another drawback of known devices consists in that they have bulky external blocks arranged to the side of the face of the watch, in which all the elements suitable to compose the winding mechanism are assembled.
For example, in U.S. Pat. No. 5,988,871 the power supply battery is placed in the cushion around which the strap of the watch to be wound is wrapped, while the entire watch winding mechanism is still at the side of the face of the watch proper, and so are the associated volumes.